Method and System for Proxy A/V Bridging on an Ethernet Switch

ABSTRACT

Aspects of a system for proxy NV bridging on an Ethernet switch may include an AV switch enables reception of incoming PDUs from a legacy device via an AV block network, wherein each incoming PDU contains an AV stream identifier (which consists of a destination address and may also consist of a traffic class designation and/or higher level protocol identifiers). The destination address may identify a destination AV device within the AV block network. The AV switch may enable generation of outgoing PDUs by inserting or modifying a corresponding traffic class designation within each of the incoming PDUs. The AV switch may enable transmission using a specific traffic shaping process of each of the outgoing PDUs to a destination AV device within the AV block network based on the AV stream identifier and corresponding QoS parameters.

CROSS-REFERENCE TO RELATED APPLICATIONS/INCORPORATION BY REFERENCE

This application makes reference to, claims priority to, and claims thebenefit of U.S. Provisional Application Ser. No. 60/917,870, filed onMay 14, 2007, which is hereby incorporated herein by reference in itsentirety.

FIELD OF THE INVENTION

Certain embodiments of the invention relate to communication networks.More specifically, certain embodiments of the invention relate to amethod and system for proxy NV bridging on an Ethernet switch.

BACKGROUND OF THE INVENTION

A/V Bridging (AVB) comprises a set of specifications, which defineservice classes (or AVB services) that enable the transport ofaudio/visual (NV) streams (and/or multimedia streams) across anAVB-enabled network (or AVB network) based on selected quality ofservice (QoS) descriptors. Specifications, which enable the definitionof AVB service classes, include the following.

A specification, which enables a set of AVB-enabled devices (or AVBdevices) within an AVB network to exchange timing information. Theexchange of timing information enables the devices to synchronize timingto a common system clock, which may be provided by a selected one of theAVB devices within the AVB network.

A specification, which enables an AVB destination device to register arequest for delivery of a specified AV stream from an AVB source device.In addition, an AVB source device may request reservation of networkresources, which enable the transmission of a specified AV stream. TheStream Reservation Protocol (SRP) defined within the specificationprovides a mechanism by which the AVB source device may register therequest to reserve resources within the AVB network (such as bandwidth)to enable the transmission of the specified AV stream. The MultipleMulticast Registration Protocol (MMRP) may enable an AVB destinationdevice to register the request for delivery of a specified AV stream.

A specification, which defines procedures by which AV streams aretransported across the AVB network. These procedures may include methodsfor the queuing and/or forwarding of the AV streams by individual AVBdevices within the AVB network.

A typical AVB network comprises a set of AVB devices, which arecollectively referred to as an AVB block. An AVB network may comprisewired local area networks (LANs) and/or wireless LANs (WLANs), forexample. Individual AVB devices within the AVB network may includeAVB-enabled endpoint computing devices (such as laptop computers andWLAN stations), AVB-enabled switching devices (AV switches) within LANsand AVB-enabled access points (APs) within WLANs, for example. Withinthe AVB block, AV destination devices may request AV streams from AVsource devices, which may be transported across the AVB network withinspecified latency target values as determined from the QoS descriptorsassociated with delivery of the AV stream.

Further limitations and disadvantages of conventional and traditionalapproaches will become apparent to one of skill in the art, throughcomparison of such systems with some aspects of the present invention asset forth in the remainder of the present application with reference tothe drawings.

BRIEF SUMMARY OF THE INVENTION

A method and system for proxy A/V bridging on an Ethernet switch,substantially as shown in and/or described in connection with at leastone of the figures, as set forth more completely in the claims.

These and other advantages, aspects and novel features of the presentinvention, as well as details of an illustrated embodiment thereof, willbe more fully understood from the following description and drawings.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a diagram illustrating an exemplary AVB network, which may beutilized in connection with an embodiment of the invention.

FIG. 2 is a diagram illustrating proxy A/V Bridging on an Ethernetswitch, in accordance with an embodiment of the invention.

FIG. 3 is a flowchart illustrating exemplary steps for enabling proxyA/V Bridging on an Ethernet switch, in accordance with an embodiment ofthe invention.

FIG. 4 is a flowchart illustrating exemplary steps for timesynchronizing AV streams at a proxy device, in accordance with anembodiment of the invention.

FIG. 5 is a flowchart illustrating exemplary steps for transporting AVstreams from a legacy device to an AVB network via a proxy AVB-enableddevice, in accordance with an embodiment of the invention.

FIG. 6 is a flowchart illustrating exemplary steps for delivery of AVstreams to a legacy device to an AVB network via a proxy AVB-enableddevice, in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Certain embodiments of the invention may be found in a method and systemfor proxy A/V bridging on an Ethernet switch. Various embodiments of theinvention comprise a method and system by which non-AVB-enabled devices(or legacy devices) may utilize AVB services, for the transmissionand/or reception of AV streams via an AVB network, which may not beavailable to legacy devices that communicate with conventional AVBnetworks.

FIG. 1 is a diagram illustrating an exemplary AVB network, which may beutilized in connection with an embodiment of the invention. Referring toFIG. 1, there is shown an AVB block 102, a legacy switch 132, a hubdevice 152, an AV device 146 and a plurality of legacy devices 142, 144and 154. The AVB block 102 may comprise a plurality of AV switches 112and 114, an AV access point (AP) 116 and a plurality of AV devices 122,124, 126 and 128.

The legacy switch 132 may comprise suitable logic, circuitry and/or codethat may enable capabilities associated with conventional data linklayer switching, for example. The legacy switch 132 may not beconfigured to provide AVB services and may therefore be referred to as anon-AVB-enabled device. The legacy switch 132 may not be configured toenable the reservation of resources for the delivery of AV streams. Thelegacy switch 132 may not be configured to enable the queuing and/orforwarding of AV streams based on QoS descriptors. In an exemplaryEthernet network, the legacy switch 132 may enable the transport ofEthernet frames on a “best effort” QoS basis. With best effort QoStransport, the latency associated with the transport of a currentEthernet frame by the legacy switch 132 may differ from the latencyassociated with the transport of a subsequent Ethernet frame. When thelegacy switch 132 receives frames from an isochronous AV stream, thevariations in latency may produce unacceptable jitter or delay when theAV stream is delivered to a destination device.

The legacy device 142 may comprise suitable logic, circuitry and/or codethat may enable capabilities associated with the transmission and/orreception of data link layer protocol data units (PDUs) to or fromconventional data link layer networks, such as conventional Ethernetnetworks. The legacy device 142 may also be referred to as anon-AVB-enabled device. In an exemplary Ethernet network, the legacydevice 142 may not be configured to exchange timing information withother Ethernet devices, or to synchronize timing to a common systemclock with other Ethernet devices. The legacy device 142 may not beconfigured to register a request for the delivery of AV streams via anEthernet network from a source device based on QoS descriptors. Thelegacy devices 144 and 154 may be substantially similar to the legacydevice 142.

The AV switch 112 may comprise suitable logic, circuitry and/or code toenable AVB services within an AVB network. An exemplary AV switch 112may be utilized in a wired LAN. The AV switch 114 may be substantiallysimilar to the AV switch 112.

The AV AP 116 may comprise suitable logic, circuitry and/or code toenable AVB services within an AVB network. An exemplary AV AP 116 may beutilized in a WLAN and/or LAN.

The AV device 122 may comprise suitable logic, circuitry and/or code toutilize AVB services. An exemplary AV device 122 may comprise acomputing device such as a laptop computer and/or WLAN station. In anexemplary Ethernet network, the AV device 122 may be configured toexchange timing information with other Ethernet devices and tosynchronize timing to a common system clock with other Ethernet devices.The AV device 122 may be configured to register requests for thedelivery of AV streams via an AVB network from a source device based onQoS descriptors. A particular set of QoS descriptors may be specifiedbased on a traffic class designation, for example. The AV devices 124,126, 128 and 146 may be substantially similar to the AV device 122.

The hub device 152 may comprise suitable logic, circuitry and/or codethat may enable repeating of signals received from one interface toother interfaces coupled to the hub device 152. In an exemplary Ethernetnetwork, the hub device 152 may enable signals received via theinterface 162 e to be transmitted via the interface 162 f. A typical hubdevice 152 may enable coupling of a plurality of interfaces, forexample, 4 interfaces, or 8 interfaces.

In an exemplary mode of operation, the legacy switch 132 may receiveand/or transmit Ethernet frames via interfaces 162 a, 162 b, 162 cand/or 162 d, wherein each of the interfaces may be coupled to adistinct port within the legacy switch 132. The legacy switch 132 maycommunicate with the AV switch via interface 162 a. The legacy switch132 may communicate with the legacy device 142 via interface 162 b. Thelegacy switch 132 may communicate with the legacy device 144 viainterface 162 c. The legacy switch 132 may communicate with the AVdevice 146 via interface 162 d. The hub device 152 may communicate withthe legacy device via interface 162 e. The hub device 152 maycommunicate with the AV switch 112 via interface 162 f. The hub device152 may enable communication between the legacy device 154 and the AVswitch 112. In a conventional Ethernet network, the legacy switch 132may transfer Ethernet frames received via one of the interfaces andtransmitted via one of the other interfaces on a best effort QoS basis.The Ethernet frames may comprise data from one or more AV streams.

The AV switch 112 may receive and/or transmit Ethernet frames viainterfaces 162 a, 162 f and 162 g, wherein each of the interfaces may becoupled to a distinct port within the AV switch 112. The AV switch 112may communicate with the legacy switch 132 via interface 162 a. The AVswitch 112 may communicate with the hub device 152 via interface 162 f.The AV switch 112 may communicate with the AV switch 114 via interface162 g. In a conventional AV network, the AV switch 112 may transferEthernet frames received and/or transmitted via one of the interfaces162 a or 162 f on a best effort QoS basis. The AV switch 112 may utilizeAVB services for the transfer of Ethernet frames received and/ortransmitted via the interface 162 g.

The AV switch 114 may receive and/or transmit Ethernet frames viainterfaces 162 g, 162 h, 162 i and 162 j, wherein each of the interfacesmay be coupled to a distinct port within the AV switch 114. The AVswitch 114 may communicate with the AV switch 112 via interface 162 g.The AV switch 114 may communicate with the AV AP 116 via interface 162h. The AV switch 114 may communicate with the AV device 122 viainterface 162 i. The AV switch 114 may communicate with the AV device126 via interface 162 j. The AV switch 114 may utilize AVB services forthe transfer of Ethernet frames received via one of the interfaces andtransmitted via one of the other interfaces.

The AV AP 116 may receive and/or transmit Ethernet frames via interfaces162 h, 162 k and 162 l, wherein each of the interfaces may be coupled toa distinct port within the AV AP 116. The AV AP 116 may communicate withthe AV switch 114 via interface 162 h. The AV AP 116 may communicatewith the AV device 124 via interface 162 k. The AV AP 116 maycommunicate with the AV device 128 via interface 162 l. The AV AP 116may utilize AVB services for the transfer of Ethernet frames receivedvia one of the interfaces and transmitted via one of the otherinterfaces. The interfaces 162 k and 162 l may comprise RF communicationchannels utilized in WLAN systems, for example.

In a conventional AV network, the AV device 146, which is shownconnected to the legacy switch 132 in FIG. 1, may be unable to utilizeAVB services, which may be available to AV devices 122, 124, 126 and 128within the AV block 102. Similarly, the legacy devices 142 and 144,which are shown as being connected to the legacy switch 132 in FIG. 1,and the legacy device 154, which is shown as being connected to the hubdevice 152, may also be unable to utilize AVB services, which may beavailable to AV devices within the AV block 102.

In various embodiments of the invention, an AV switch 112 within the AVblock 102 may enable a legacy device 154, which is outside of the AVblock 102, to utilize AVB services. This may occur when a port on the AVswitch 112 communicates with a single device. As shown in FIG. 1, theport on the AV switch 112, which is coupled to the interface 162 f, maycommunicate with a single device, that device being the legacy device154 (via the hub device 152). In this aspect of the invention, while thelegacy device 154 may remain a non-AVB-enabled device, the AV switch 112may act as a proxy for the legacy device 154 within the AV block 102,thereby enabling the utilization of AVB services for the transport of AVstreams, which are transmitted and/or received by the legacy device 154,within the AV block 102.

FIG. 2 is a diagram illustrating proxy A/V Bridging on an Ethernetswitch, in accordance with an embodiment of the invention. Referring toFIG. 2, there is shown an AVB block 202, a legacy switch 132, an AVdevice 146 and legacy devices 142 and 144. The AVB block 202 maycomprise a plurality of AV switches 112 and 114, an AV access point (AP)116, a legacy device 154 and a plurality of AV devices 122, 124, 126 and128.

In comparing FIG. 2, to FIG. 1, FIG. 2 shows a logical connectionbetween the AV switch 112 and the legacy device 154 via the interface162 f. In this representation, the AV switch 112 acts as a proxy for thelegacy device 154 within the AV block 202 via interface 162 f, whichenables the legacy device 154 to utilize AVB services within the AVblock 202. Consequently, the legacy device 154 is shown as being withinthe AV block 202 in FIG. 2 via the logical connection to the interface162 f.

In various embodiments of the invention, AV devices, AV switches and/orAV APs associate within an AV block 202 based on the exchange ofdiscovery protocol (e.g. “Logical Link Discovery Protocol”: LLDP)messages, which may be periodically transmitted from the respectivedevices. The discovery protocol messages describe the attributes of thedevice, which is sending the message. For example, the AV device 122 maytransmit discovery protocol messages, which describe the attributes ofthe AV device 122 via interface 162 i. Similarly, the AV device 124 maytransmit discovery protocol messages, which describe the attributes ofthe AV device 124 via interface 162 k. The AV switch 114 may transmitdiscovery protocol messages, which describe the attributes of the AVswitch 114 via interfaces 162 g, 162 h, 162 i and 162 j. The AV switch112 may receive discovery protocol messages from the AV switch 114 viainterface 162 g. The AV AP 116 may receive discovery protocol messagesfrom the AV switch 114 via interface 162 h. The AV device 122 mayreceive discovery protocol messages from the AV switch 114 via theinterface 162 i. The AV device 126 may receive discovery protocolmessages from the AV switch 114 via interface 162 j. The AV switch 114may receive discovery protocol messages from the AV switch 122 viainterface 162 g. The AV switch 114 may receive discovery protocolmessages from the AV AP 116 via interface 162 h. The AV switch 114 mayreceive discovery protocol messages from the AV device 122 via interface162 i. The AV switch 114 may receive discovery protocol messages fromthe AV device 126 via interface 162 j.

An AVB-enabled device may send discovery protocol messages, which maycomprise a “time-synch” capable attribute and an AV-capable attribute.An AVB-enabled device, which receives a discovery protocol message,which comprises the time-synch-capable attribute and AV-capableattribute via a port, may label the port to be an “AVB” port. At an AVdevice 122, 124, 126 or 128, the labeling of the port to be an AVB portmay enable the AV device to utilize AVB services within the AV block202. At an AV switch 112 or 114, or at an AV AP 116, the labeling of aport as an AVB port may enable the port to be utilized for AVB services.The AV devices, which are reachable via the port, may be referred to as“participating” devices. The participating devices may utilize AVBservices within the AV block 202.

Within the AV block 202, a plurality of ports at various AV switches 112or 114, or at the AV AP 116 may enable the formation of paths between AVdevices within the AV block 202. For example, a path between theparticipating AV device 122 and the participating AV device 124 maycomprise interface 162 i, the AV switch 114, interface 162 h, the AV AP116 and the interface 162 k. When the ports located at the AV switch114, which are connected to the interfaces 162 i and 162 h, and the portlocated at the AV AP 116, which are connected to the interfaces 162 hand 162 k are each labeled to be an AVB port, then a path may existwithin the AV block 202, which may enable the transport of AV streamsbetween the participating AV device 122 and the participating AV device124.

In conventional AVB networks, an AVB-enabled device, which does notreceive a discovery protocol message that comprises thetime-synch-capable attribute and the AV-capable attribute via a port,may label the port to be a “legacy” port. Labeling of a port within anAVB-enabled device as a legacy port may disable AVB services at theport.

In various embodiments of the invention, however, a legacy device 154may send a discovery protocol message to a port located within an AVswitch 112, which comprises a “proxy request” attribute. In theexemplary AV block 202 shown in FIG. 2, the AV switch 112 may receivethe discovery protocol messages from the legacy device 154 at a portwithin the AV switch 112, which is coupled to the interface 162 f.Receipt of the discovery protocol messages may enable proxy services atthe port within the AV switch 112 when the AV switch 112 detects that asingle Ethernet-addressable device is reachable via the port. The AVswitch 112 may determine whether a single Ethernet-addressable device isreachable via the port by inspecting the source address fields withinreceived Ethernet frames, for example. When the Ethernet frames receivedat a port within the AV switch 112 comprise a source address field,which references a single Ethernet address, the AV switch 112 maydetermine that a single Ethernet-addressable device is reachable via theport.

By providing proxy services to the legacy device 154, the AV switch 112may enable the legacy device 112 to utilize AVB services within the AVblock 202. The legacy device, which is reachable via the port, may bereferred to as a “semi-participating” device. The semi-participatinglegacy device 154 may utilize AVB services within the AV block 202, evenif the semi-participating legacy device 154 is not enabled to requestspecific AVB services. In this aspect of the invention, the AV switch112 may request the AVB services on behalf of the semi-participatinglegacy device 154.

In one aspect of the invention, the AV switch 112 may provide proxyservices on behalf of the legacy device 154 by enabling timesynchronization between the legacy device 154 and the system clockutilized within the AV block 202. In various embodiments of theinvention, the AV switch 112 may perform the timing synchronization whenthe legacy device 154 is acting as a source device, which transmits AVstreams to one or more destination devices within the AV block 202, forexample the AV device 122.

In various embodiments of the invention, the proxy AV switch 112 maytime synchronize the AV streams transmitted by the legacy device 154 tothe receiving AV device 122 by providing traffic shaping services forparticular AV stream transmitted by the legacy device 154. Theparticular AV stream may be determined by a specific combination ofdestination address, priority tag, and higher-level protocol information(e.g., IP port number). The particular traffic shaping rules may bedetermined by the QoS information obtained from a reservation protocol,utilized in various embodiments of the invention, or by examining thereceived traffic and estimating the QoS information. The traffic shapingof the Ethernet frames may enable the AVB network to transport theEthernet frames along a path within the AV block 202 such that thelatency of the transport along the path is within specified latencytarget values. For example, the path from the legacy device 154 to theAV device 122 may comprise interface 162 f, the AV switch 112, interface162 g, the AV switch 114 and interface 162 i. Along the path, the AVswitch 112 may utilize the QoS information to determine the process forthe queuing and forwarding of Ethernet frames received via the interface162 f and forwarded via the interface 162 g. Similarly, the AV switch114 may utilize the QoS information to determine the process for thequeuing and forwarding of Ethernet frames received via the interface 162g and forwarded via the interface 162 i.

Since the legacy device 154 is not synchronized to a common system clockwithin the AV block 202, jitter within the AV stream transmitted fromthe legacy device 154 to the AV device 122 may be greater than may bethe case when the path is between two AV devices, for example an AVdevice 122 which transmits an AV stream to the AV device 124. In thisaspect of the invention, the AV switch 112 may reduce the jitter inEthernet frames received from the legacy device 154, measured at theinterface 162 f, by providing the traffic shaping services describedabove.

In various embodiments of the invention, in which the legacy device 154transmits AV streams which do not utilize AV Bridging services, forexample when legacy device 154 transmits a standard RTP (real timeprotocol) stream, the AV stream may be transported across the AV block202 utilizing legacy timing mechanisms.

In another aspect of the invention, the AV switch 112 may provide proxyservices on behalf of the legacy device 154 by enabling registration ofrequests for delivery of AV streams from an AVB source device, when thelegacy device 154 is a destination for the AV stream. When the legacydevice 154 is a source for the AV stream, the AV switch 112 may enablesending of requests for the reservation of resources within the AV block202 on behalf of the legacy device 154.

When the legacy device 154 is a source for the AV stream, the AV switch112 may detect Ethernet frames received from the legacy device 154.Based on the detections, the AV switch 112 may generate a trafficprofile for the AV streams. For example, the AV switch 112 may determinethat the generated traffic profile for the received AV stream maycorrespond to an RTP profile for an MPEG-2 stream. Based on thegenerated traffic profile, the AV switch 112 may generate a set ofreservation parameters, for example QoS descriptors. The AV switch 112may then generate a reservation request message (e.g, “StreamReservation Protocol”: SRP, or “Multiple Stream Reservation Protocol”:MSRP) on behalf of the legacy device 154, which incorporates thegenerated set of reservation parameters. The AV switch 112 may propagatethe generated reservation message among AVB-enabled devices within theAV block 202.

In various embodiments of the invention, when the legacy device 154 iscapable of generating a reservation request message on its own behalf,the legacy device 154 may send the reservation request message to the AVswitch 112 via the interface 162 f. When the legacy device 154 is asemi-participating device, the AV switch 112 may propagate the receivedreservation message among AVB-enabled devices within the AV block 202.

When the legacy device 154 is a destination for the AV stream, the AVswitch 112 may detect Ethernet frames, which are being forwarded to thelegacy device 154. Based on the detections, the AV switch 112 maygenerate a traffic profile for the AV streams. Based on the generatedtraffic profile, the AV switch 112 may generate a set of QoSdescriptors. The AV switch 112 may then generate a registration requestmessage on behalf of the legacy device 154, which incorporates thegenerated set of QoS descriptors. The AV switch 112 may then propagatethe generated registration request message among AVB-enabled deviceswithin the AV block 202.

In various embodiments of the invention, when the legacy device 154 iscapable of generating a registration request message on its own behalf,the legacy device 154 may send the registration request message to theAV switch 112 via the interface 162 f. When the legacy device 154 is asemi-participating device, the AV switch 112 may propagate the receivedregistration request message among AVB-enabled devices within the AVblock 202.

FIG. 3 is a flowchart illustrating exemplary steps for enabling proxy NVBridging on an Ethernet switch, in accordance with an embodiment of theinvention. Referring to FIG. 3, in step 302, a discovery protocolmessage may be received at port within an AV switch 112. Step 304 maydetermine whether the discovery protocol message includes time-synch andAV attributes. When step 304 determines that the attributes may bepresent in the received discovery protocol message, in step 306, theswitch port may be labeled an AVB port. In step 308, devices reachablevia the port may be determined to be participating devices within an AVBblock 202.

When step 304 determines that the time-synch and AV attributes may notbe present in the received discovery protocol message, in step 310, theswitch port may be labeled a legacy port. Step 312 may determine whethera single Ethernet-addressable device may be reachable via the labeledlegacy port. When step 312 determines that more than a single device isreachable via the labeled legacy port, in step 314, the switch port maybe determined to be not proxy enabled.

When step 312 determines that a single Ethernet-addressable device maybe reachable via the labeled legacy port, step 316 may determine whethera proxy request attribute was included in the received discoveryprotocol message. When step 316 determines that a proxy requestattribute was not included in the received discovery protocol message,step 314 may follow.

When step 316 determines that a proxy request attribute was included inthe discovery protocol message, step 318 may determine that the switchport is to be proxy enabled. In step 320, the device reachable via theport may be determined to be a semi-participating device.

FIG. 4 is a flowchart illustrating exemplary steps for timesynchronizing AV streams at a proxy device, in accordance with anembodiment of the invention. Referring to FIG. 4, in step 402 an AVswitch 112 may receive Ethernet frames from a legacy device 154. TheEthernet frames may comprise portions of an AV stream generated by anapplication within the legacy device 154. Step 404 may determine whetherthe protocol executing within the legacy device 154 utilizes AVBservices. When step 404 determines that the protocol does not utilizeAVB services, in step 406, the AV switch 112 may transport the Ethernetframes using legacy transport mechanisms.

When step 404 determines that the protocol does utilize AVB services, instep 408, the AV switch 112 may transport the Ethernet frames within theAV block 202 utilizing AVB services. The AV switch 112 may apply trafficshaping rules specified by the QoS parameters for the AV stream beforetransporting the Ethernet frames within the AV block 202. The AV switch112 may identify the AV stream by a destination address and/or higherlayer information. The QoS parameters may be determined based on areservation protocol. The QoS parameters may be determined by examiningthe received Ethernet frames, which may enable identification of apotential AV stream and measurement of timing of Ethernet framesreceived in the potential AV stream to determine jitter and bandwidthestimates.

FIG. 5 is a flowchart illustrating exemplary steps for transporting AVstreams from a legacy device to an AVB network via a proxy AVB-enableddevice, in accordance with an embodiment of the invention. FIG. 5presents an exemplary method by which an AV switch 112 may forward AVstreams within an AV block 202, utilizing AVB services, on behalf of alegacy device 154. In FIG. 5, the legacy device 154 may be assumed to bea semi-participating device. Referring to FIG. 5, in step 502, the AVswitch 112 may receive Ethernet frames from the legacy device 154. TheEthernet frames may comprise portions of data from the AV stream. Step504 may determine whether a received Ethernet frame contains areservation message. When the AV switch 112 receives a reservationmessage from the legacy device 154, in step 508, the AV switch 112 maypropagate the received reservation message within the AV block 202.

When step 504 determines that the received Ethernet frames do notcontain a reservation message, in step 510, the AV switch 112 maydetermine whether the legacy device 154 had previously sent areservation message. When the AV switch 112 determines, in step 510,that the legacy device 154 had previously sent a reservation message, instep 512, the AV switch 112 may transport the received Ethernet frameswithin the AV block 202 using AVB services. The AV switch 112 mayprovide traffic shaping services for the Ethernet frames beforetransporting the Ethernet frames within the AV block 202. The AV switch112 may also insert a traffic class designation or change an existingtraffic class designation within the Ethernet frames prior totransporting the Ethernet frames within the AV block 202.

When the AV switch 112 determines, in step 510, that the legacy devicehad not previously sent a reservation message, in step 514, the AVswitch 112 may detect AV streams and estimate QoS descriptors based onthe headers and content of Ethernet frames received from the legacydevice 154. The estimated QoS descriptors may account for jitter andbandwidth usage detected in the received Ethernet frames from the legacydevice 154. In step 516, the AV switch 112 may generate a reservationmessage on behalf of the legacy device 154 based on the estimated QoSdescriptors. In step 518, the AV switch 112 may propagate the generatedSRP reservation message within the AV block 202.

FIG. 6 is a flowchart illustrating exemplary steps for delivery of AVstreams to a legacy device to an AVB network via a proxy AVB-enableddevice, in accordance with an embodiment of the invention. FIG. 6presents an exemplary method by which an AV switch 112 may utilize AVBservices to forward AV streams from an AVB-enabled device within an AVblock 202 to a legacy device 154. In FIG. 6, the legacy device 154 maybe assumed to be a semi-participating device. Referring to FIG. 6, instep 602, the AV switch 112 may receive Ethernet frames, which areaddressed for delivery to the legacy device 154. The Ethernet frames maycomprise portions of data from the AV stream. In step 604, the receivedEthernet frames may be forwarded to the legacy device 154. Step 606 maydetermine whether the AV switch 112 has received a registration requestmessage (e.g: “Multiple Multicast Registration Protocol”: MMRP) from thelegacy device 154. When the AV switch 112 determines, in step 606, thata registration request message has been received from the legacy device154, in step 610, the AV switch 112 may propagate the receivedregistration request message within the AV block 202.

When the AV switch 112 determines, in step 606, that a registrationrequest message has not been received from the legacy device 154, instep 612, the AV switch 112 may estimate QoS descriptors based on theEthernet frames forwarded to the legacy device 154. In step 614, the AVswitch 112 may generate a registration request message on behalf of thelegacy device 154. In step 616, the AV switch 112 may propagate thegenerated registration request message within the AV block 202.

Aspects of a system for proxy A/V bridging on an Ethernet switch maycomprise an AV switch 112, which enables reception of incoming PDUs froma legacy device 154 via an AV block network 202, wherein each incomingPDU contains an AV stream identifier. The AV stream identifier consistsof a destination address, traffic class identifier, and may also includea higher level protocol identifier (such as IP port number). Thedestination address may identify a destination AV device 122 within theAV block network 202. The AV switch 112 may enable generation ofoutgoing PDUs by inserting or modifying a corresponding traffic classdesignation within each of the incoming PDUs. The AV switch 112 mayenable transmission of each of the outgoing PDUs to a destination AVdevice 122 within the AV block network 202 based on the AV streamidentifier.

The AV switch 112 enables generation or modification of thecorresponding traffic class designation based on a reservation messagereceived from the legacy device 154. The AV switch 112 may enabletransmission to propagate the received reservation message within the AVblock network 202.

The AV switch 112 may enable generation of QoS descriptors based on theincoming PDUs received from the legacy device 154. The AV switch 112 mayenable estimation of timing jitter and bandwidth of the received AVstreams, where the AV streams may be identified based on address,traffic class, and/or higher level identifiers of incoming PDUs. Thegenerated QoS descriptors may be adjusted based on the estimated timingjitter and bandwidth. The AV switch 112 may enable generation of areservation message for an AV stream based on the generated QoSdescriptors. The AV switch 112 may enable transmission to propagate thegenerated reservation message within the AV block network 202. The AVswitch 112 may enable generation or modification of the correspondingtraffic class designation based on the generated reservation message.

Aspects of a system for proxy NV bridging on an Ethernet switch maycomprise an AV switch 112 receiving discovery protocol messages via aport. The AV switch may label the port based on the contents of thereceived discovery protocol message. The AV switch 112 may determinewhether a communicating device, such as a legacy device 154, may utilizeAVB services for transmitting and/or receiving PDUs via the port basedon the labeling.

The communicating device may be enabled to utilize AVB services via theport when the discovery protocol message comprises atime-synchronization-enabled attribute and an AV-enabled attribute. Theport may be labeled as a legacy port when the discovery protocol messagedoes not comprise a time-synchronization-enabled attribute and anAV-enabled attribute. When the port is labeled as a legacy port, alegacy device 154 may be enabled to utilize AVB services via the portwhen the discovery protocol message comprises a proxy request attribute.The port may be labeled as a proxy enabled port when the discoveryprotocol message comprises the proxy request attribute. A single legacydevice 154 may transmit and/or receive PDUs via the labeled proxyenabled port.

Another embodiment of the invention may provide a machine-readablestorage, having stored thereon, a computer program having at least onecode section executable by a machine, thereby causing the machine toperform the steps as described herein for proxy A/V bridging on anEthernet switch.

Accordingly, the present invention may be realized in hardware,software, or a combination of hardware and software. The presentinvention may be realized in a centralized fashion in at least onecomputer system, or in a distributed fashion where different elementsare spread across several interconnected computer systems. Any kind ofcomputer system or other apparatus adapted for carrying out the methodsdescribed herein is suited. A typical combination of hardware andsoftware may be a general-purpose computer system with a computerprogram that, when being loaded and executed, controls the computersystem such that it carries out the methods described herein.

The present invention may also be embedded in a computer programproduct, which comprises all the features enabling the implementation ofthe methods described herein, and which when loaded in a computer systemis able to carry out these methods. Computer program in the presentcontext means any expression, in any language, code or notation, of aset of instructions intended to cause a system having an informationprocessing capability to perform a particular function either directlyor after either or both of the following: a) conversion to anotherlanguage, code or notation; b) reproduction in a different materialform.

While the present invention has been described with reference to certainembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted withoutdeparting from the scope of the present invention. In addition, manymodifications may be made to adapt a particular situation or material tothe teachings of the present invention without departing from its scope.Therefore, it is intended that the present invention not be limited tothe particular embodiment disclosed, but that the present invention willinclude all embodiments falling within the scope of the appended claims.

1. A method for communicating data, the method comprising: receiving atleast one incoming protocol data unit via a network, wherein each ofsaid at least one incoming protocol data unit comprises a destinationaddress; generating a corresponding at least one outgoing protocol dataunit by inserting a traffic class designation within each of said atleast one incoming protocol data unit; and transmitting saidcorresponding at least one outgoing protocol data unit based on saiddestination address, said inserted traffic class designation and/orhigher layer protocol identifiers.
 2. The method according to claim 1,comprising generating said traffic class designation based on a receivedreservation message.
 3. The method according to claim 2, comprisingtransmitting said received reservation message.
 4. The method accordingto claim 1, comprising generating quality of service descriptors basedon said received at least one incoming protocol data unit.
 5. The methodaccording to claim 4, comprising estimating timing jitter and/orbandwidth in said received at least one incoming protocol data unit. 6.The method according to claim 5, comprising adjusting said generatedquality of service descriptors based on said estimated timing jitterand/or bandwidth.
 7. The method according to claim 4, comprisinggenerating a reservation message based on said generated quality ofservice descriptors.
 8. The method according to claim 7, comprisingtransmitting said generated reservation message.
 9. The method accordingto claim 7, comprising generating said traffic class designation basedon said generated reservation message.
 10. A system for communicatingdata, the system comprising: one or more circuits that enable receptionof at least one incoming protocol data unit via a network, wherein eachof said at least one incoming protocol data unit comprises a streamidentifier; said one or more circuits enable generation of acorresponding at least one outgoing protocol data unit by inserting atraffic class designation within each of said at least one incomingprotocol data unit; and said one or more circuits enable transmission ofsaid corresponding at least one outgoing protocol data unit based onsaid stream identifier and/or said inserted traffic class designation.11. The system according to claim 10, wherein said one or more circuitsenable generation of said traffic class designation based on a receivedreservation message.
 12. The system according to claim 11, wherein saidone or more circuits enable transmission of said received reservationmessage.
 13. The system according to claim 10, wherein said one or morecircuits enable generation of quality of service descriptors based onsaid received at least one incoming protocol data unit.
 14. The systemaccording to claim 13, wherein said one or more circuits enableestimation of timing jitter and/or bandwidth in said received at leastone incoming protocol data unit.
 15. The system according to claim 14,wherein said one or more circuits enable adjustment of said generatedquality of service descriptors based on said estimated timing jitterand/or bandwidth.
 16. The system according to claim 13, wherein said oneor more circuits enable generation of a reservation message based onsaid generated quality of service descriptors.
 17. The system accordingto claim 16, wherein said one or more circuits enable transmission ofsaid generated reservation message.
 18. The system according to claim16, wherein said one or more circuits enable generation of said trafficclass designation based on said generated reservation message.
 19. Amethod for communicating data, the method comprising: receiving a linkdiscovery message via a port; labeling said port based on the contentsof said received link discovery message; and determining whether acommunicating device may utilize AV Bridging services for transmittingand/or receiving protocol data units via said port based on saidlabeling.
 20. The method according to claim 19, wherein saidcommunicating device is enabled to utilize said AV Bridging services viasaid port when said link discovery message comprises atime-synchronization-enabled attribute and an AV-enabled attribute.21-30. (canceled)